People who sleep less than 6 hours a night in their 50’s and 60’s may be at increased risk of developing dementia in old age, according to a new study published in Nature Communications. Recent studies indicate that the development of dementia occurs over many years and decades, identifying lifestyle habits and treatable conditions early in the lifecourse that might predispose people to dementia. In their Nature Communications article, Séverine Sabia and colleagues examined whether sleep duration at age 50, 60 or 70 could be connected with the development of dementia in older age. Using data from the Whitehall Cohort study, which started recruiting participants in the 1980’s, the researchers identified 7959 participants with almost 30 years of follow-up. Of these, 521 developed dementia during the follow-up period, with an average age of diagnosis of 77 years.
Dividing participants into groups according to their sleep duration (low <6h, normal = 7h, high >8h), the researchers found that individuals who slept less than 6h at age 50 or 60 had approximately 30% higher risk of developing dementia in later life, compared to people who slept 7h or more. This association persisted even when correcting for known dementia risk factors such as cardiovascular disease, marriage status and BMI.
